This invention relates to a chuck head for a rotatable feeding movement of a clamped ring shaped body, for instance of a ferrite toroid core, wound on on a microtoroid winding machine. The arrangement represents a unit, which can be used as additional replaceable part of a microtoroid winding machine.
Actually used microtoroid winding machines enable an automatic winding of miniature toroids up to a minimum external diameter of about 4 mm. For winding of toroid cores of a smaller external diameter, for instance 2.5 mm only, a special exchangeable additional arrangement, a chuck head with a rotatable feeding movement had to be designed.
The arrangement now used for clamping and feeding of toroids had the toroid core, on which the conductor had to be wound, clamped between three guiding rollers, one of which was idle running, tiltable, designed for securing pressure only, whereas the remaining two rollers received a step by step rotating motion from the shaft of a ratchet wheel by way of a toothed gear. The shafts of the driven rollers together with the rollers and their pinions have been arranged rotatably between two flat parallel side walls, forming the supporting structure of the clamping device. This arrangement did not allow the winding of very small toroids, because their clamping required already the use of clamping rollers of very small diameters situated at rather limited axial distances. Any reduction of the axial distances of clamping rollers caused difficulties of the design of the discriminating device, used for winding the conductor on the core, the arm of which had to be brought as close as possible to the face of the wound on toroid. The reduction of the axial distance of the clamping rollers has been in known designs of microtoroid winding machines limited by the circumstance that the arm of the discriminating device had to perform working movements between the shafts of the clamping rollers and bearing parts of these shafts. The rotatable feeding of very small toroids with a step by step drive of only two of three clamping rollers has not been reliable due to slipping. This drawback could not been eliminated by application of a larger pressure of the pressure roller both because of the brittleness of very small toroids and because very small toroids have been in case of larger pressures pressed into the rubber lining of the clamping rollers what additionally affected the conditions for a reliable feeding movement of the toroid.